The jet went down over Kayah State in eastern Myanmar, near the border with Thailand, on Saturday during fighting between the military and the Karenni Nationalities Defence Force (KNDF), which said it shot down the plane.

Junta spokesperson Zaw Min Tun told state-run MRTV the jet crashed due to a technical problem and the pilots had ejected safely and were in contact with the military.

The incident comes as Myanmar's military battles opposition forces on multiple fronts, as ethnic minority forces and anti-junta militias mount a rebellion that security analysts say is being carried out with an unprecedented level of coordination.

The military-installed president last week said Myanmar was at risk of breaking apart due to the failure to deal with the insurgency more effectively.

Conflict in Shan State, in the northeast bordering China, has displaced at least 50,000 people, with trade routes cut off and several towns seized since an anti-junta offensive launched last month by three ethnic minority insurgent groups.

China has called for all sides to cease hostilities.

The insurgent alliance says it has seized more than 100 army posts. Assaults on towns have also taken place in Sagaing region, in central Myanmar, west of Shan State.

Hundreds of foreign workers, many of whom rights activists say are victims of human trafficking, are trapped by the fighting, including citizens of Vietnam and of Thailand.

The Thai foreign ministry said on Saturday 200 of its nationals were waiting to be evacuated "as soon as possible when the situation permits".

The KNDF said on its Facebook page it shot down the jet on Saturday using heavy machine guns and its members were searching for the pilots.

Reuters could not verify the information.

News outlet Mizzima on its Facebook page posted images of what it said were the abandoned helmet and parachute of one of the pilots.